This invention relates to facsimile transmission systems and methods for sending a document between a sender and a receiver by facsimile in a manner which prevents unauthorized casual reading of the document, and, more particularly, to a printing medium for the printing of images thereon to form a document by the printer of a standard facsimile machine in a manner which renders the document unreadable to a casual observer comprising a strip of a flexible printing medium receivable by the facsimile machine for passage therethrough past the printer thereof, said printing medium having a surface for receiving an image from the printer; and, a strip of an obscuring medium removably attached to the printing medium along an edge thereof in a manner which will allow the obscuring medium to pass through the facsimile machine in combination with the printing medium, the obscuring medium having an obscuring portion covering a printing surface of the printing medium upon which the printer prints images for rendering printing on the printing medium unreadable to a casual observer.
In the above-referenced, co-pending '700 application, the teachings of which are incorporated herein by reference, a method and associated apparatus is disclosed by means of which a document can be transmitted between a sender and a receiver by facsimile in a manner which prevents unauthorized casual reading of the document. A pair of patterns are alternately placed over the document while it is scanned (either by a photocopy machine or the scanning head of a facsimile machine). Each pattern contains white portions on a transparent background thus creating transparent portions. The patterns are complementary and mutually exclusive; that is, the "A" pattern has white portions where the "B" pattern has transparent portions, and also vice versa. Thus, when a document is scanned through the "A" pattern, a first partial document is produced. Similarly, when the document is scanned through the "B" pattern, a second partial document is produced. The partial documents can also be produced by software operating on a document produced by a word processing program. Regardless of the method of origination, the two partial documents are then transmitted by facsimile to the receiver. At the receiving end, the two partial documents are difficult to read and understand, at least to the casual observer. To "read" the original document, the intended receiver makes a copy of one of the two partial documents on a transparency and only has to place the transparency over the other partial document in proper registration in order to view (and copy, if desired) the reconstructed document.
In the above-referenced, co-pending '975 application, the teachings of which are also incorporated herein by reference, a method and associated apparatus are disclosed whereby the transparency and the other partial document are adhesively connected together to form a complete document which can be stored, copied, read, etc., with convenience.
As will be recognized readily by those skilled in the art, the foregoing methods and apparatus of the co-pending applications of which this is a continuation-in-part are directed to a security facsimile transmission system wherein the secure transmission is initiated by the sender. What is also needed is a security facsimile transmission system wherein the secure transmission can be under the control of the receiver.
Wherefore, it is the object of this invention to provide a facsimile transmission receiving medium onto which a received facsimile from a standard facsimile machine can be printed in a manner which will make the resultant copy virtually unreadable to the casual observer.
It is another object of this invention to provide a facsimile transmission receiving medium onto which a received facsimile can be printed in a manner which will make the resultant copy virtually unreadable to the casual observer whether the standard facsimile machine receiving and printing the document being transmitted is of the thermal printing variety or of the type printing on plain paper employing a toner.
Other objects and benefits of this invention will become apparent from the detailed description which follows hereinafter when taken in conjunction with the drawing figures which accompany it.